Known single-chamber filling systems are only suitable for pressurized filling of a container that is sealed against a filling element of the filling system. In such systems, pressure within the product vessel holds the filling element's liquid valve closed until a pressure balance occurs between the vessel and the container's interior. This occurs when a gas valve in a gas channel opens to connect the container's interior to the vessel. As a result, a liquid valve opens.
Filling under reduced pressure is difficult with known filling systems mainly because of friction forces associated with moving a valve body and/or its valve tappet during opening and closing.
A further disadvantage of the known filling system is the presence of closing springs, guides, and/or fixing elements of the filling elements in the vessel's interior. These pose a hygiene risk.